1. Field
The present disclosure relates to a shielded wire and a communication system.
2. Description of Related Art
A shielded wire such as that disclosed in Japanese Patent Application Publication No. 2013-109919 (JP 2013-109919 A) has been known. In general, the shielded wire that is connected to a high-voltage system or a low-voltage system includes a wire section, a shielding layer for covering the wire section, and a sheath for covering the shielding layer.
When the sheath is peeled from a tip of the shielded wire, the shielding layer is exposed. A ground terminal is attached to a tip of the shielding layer (also referred to as a drain wire). A ground connection is made when the ground terminal is fixed to a metal plate, a vehicle body, or the like. Meanwhile, a wire is exposed in a portion from which the sheath and the shielding layer are skinned. A connection terminal is attached to the wire (a core wire), and the connection terminal is connected to an electrical component that is accommodated in a shielding case or the like.
In general, the shielding layer of the shielded wire is subjected to the ground connection via the drain wire. Here, it is assumed that the shielding layer of the shielded wire (high-voltage wiring), which is connected to the high-voltage system, is subjected to the ground connection and that the shielding layer of the shielded wire (low-voltage wiring), which is connected to the low-voltage system, is also subjected to the ground connection. According to this structure, communication performance of the low-voltage wiring can be secured.
Here, a reference potential that is used for high-voltage communication is sufficiently higher than a reference potential that is used for low-voltage communication. A potential variation value between the potential that is used for the high-voltage communication and a ground potential differs from a potential variation value between the potential that is used for the low-voltage communication and the ground potential. Thus, a large potential variation difference is generated between the high-voltage wiring and the low-voltage wiring (the ground potential). In the case where the high-voltage wiring and the low-voltage wiring (or the ground potential) are arranged near each other, due to coupling of stray capacitances, filters, or the like, the potential variation difference between a communication reference wire of the high-voltage wiring and the low-voltage wiring (or the ground potential) is possibly superposed as noise on the high-voltage wiring, and thus the high-voltage communication does not possibly function normally.